Matlab and Optisystem which is wrong?

[Abdallah IsmailParticipant]

I made matlab component to get the optical system in the time domain ,then when I use FFT and divide it by the total no. of input signal samples,then I get the signal to matlab in frequency domain,I found it doesn’t match exactly with FFT .not only the values but also the signs.
What is the difference and what is the right matlab or Optisystem.
this is part of modeling fiber with SSFM which doesn’t give accurate results and I’m trying to find the cause of the problem.
Regards,
Abdallah

[Damian MarekParticipant]

Hi Abdallah,

There can be some differences in how a Fourier transform is defined. That being said could you please attach your project file, matlab component file and the plots that don’t match?

Thanks

[Abdallah IsmailParticipant]

Thanks Damian for your response.
I modified the code to be readable for you.
You’ll conclude from the code how to run it.
Run the time domain first then frequncy domain after removing % % from frequency domain part and adding % to time domain part.
Compare Optisystem_signal with Matlab_signal.
Although the power results is very close but the samples are not the same.
I Hope you tell me how the optisystem make fft.
Regards,

Attachments:

1. FFT_test.osd
2. fft_test.m

[JamalParticipant]

If we export the signal in frequency domain then we get the signal in power ?

Can anyone confirm this ?

[Ranjeet KumarParticipant]

Hi Abdallah,
I think you have problem in matlab code because when i simulate the program using optisystem, i got the error as” CIDF scheduler :error occured while calculating , component MATLAB component Error in MAtlab program”.
So, I think we should correct the Matlab code.
There is no problem in optisystem.

Attachments:

1. 

   Capture23.jpg
   

[SAHIL SINGHParticipant]

Hi Abdullah,

As mentioned by Ranjeet, if there occurs an error showing “MATLAB component Error in MAtlab program”, then definitely you should correct the Matlab code… Hope it helps…

Regards

Sahil Singh

+1

[JamalParticipant]

Ranjeet
Can you confirm if the signal exported in frequency domain has amplitude in Watts ?